Welcome to the Cofrin Center for Biodiversity

Ecology

Geology

Green Bay, formerly a river, was widened and deepened during the late Pleistocene by the Green Bay Lobe of the Wisconsin glacial series. The glacial activity left a gradual deepening from west to east. At midbay, the depth levels off until it rises abruptly on the east shore. The difference in contour in the bay results in the contrasting development of wetland vegetation on both sides of the bay. Due to the steep slopes, Point au Sauble contains one of the only large wetlands on the east shore of Green Bay.

aerial map of the point Natural Communities

Point au Sauble encompasses a variety of terrestrial and aquatic habitats. Communities vary depending on hydrology. As water levels change habitats succeed or change from one type to another. The most extensive natural communities represented today are:

Floodplain forest
Shrub-carr
Sedge meadow
Emergent aquatic
Open water
Great Lakes beach

Biota

An inventory of plants and animals at Point au Sauble is being developed. Extensive bird research is ongoing and has resulted in an extensive species list. Amphibians and reptiles have also been surveyed. Graduate student Brad Herrick recently finished his masters thesis on the aquatic plant communities and a plant list will soon be available.

Hyrology

The varying water levels play a critical role in determining which communities persist in the Pt. au Sauble landscape. Recent low water levels in Green Bay illustrate the dynamic interactions between the the bay and adjacent habitats. Water level changes most drastically affect the vegetation in marshes on Point au Sauble and other coastal wetlands. During periods of persistent high water, the open water complex develops across most of the low areas. In years of extremely low water, like 1999, large areas of mud flat are exposed in the lagoon and marsh. Annuals such as soft-stemmed bullrush (Scirpus validus) recolonize the exposed flats and become a dominant feature of the wetland vegetation. As the water levels return to normal, the marsh will slowly succeed back to cattails (Typha spp.).

Biodiversity Topics: Introduction . Plants . Animals . Mammals . Birds . Reptiles & Amphibians . Arthropods . Spiders . Insects